IN these days of hi-tech engines, the distinctive sound of single-cylinder old motorcycles is a breath of nostalgia.

South-west Victorian roads this week will be reverberating to the exhaust notes of 100 fastidiously restored bikes for the national Velocette Good Companions Rally.

There will be 80 Velocettes plus 20 other classic marques.

Riders, from as far as the US and New Zealand, yesterday left the rally base at the Warrnambool Army Reserve barracks for a jaunt to Macarthur and Mount Eccles.

They will visit Tower Hill and Port Fairy today before leaving Wednesday for three days along the Great Ocean Road and the Otways. Velocettes were manufactured in England between 1913 and 1971. At various times they were the fastest racing machines on the market and are now highly sought after by enthusiasts.

Almost 50 years ago a Velocette set a world record for an average speed of 100 miles an hour (160kmh) for 24 hours. The record still stands.

More than 160 enthusiasts have registered for the Warrnambool rally which organiser Neville Smith is confident will be one of the best ever. By the time of Friday's farewell dinner comes around the riders will be a little saddle sore after having covered more than 800 kilometres.

"We have set an interesting route covering some of the region's best scenery," he said.